Use postgres DB for package

I want to connect a package which is able to add and list some events (meaning dates) to a postgres database.
My setup:
I have a MAMPstack from bitnami extended by the postgres-module. I installed the newest (5.7.5.4) concrete5 version and everything is fine. I can use the package with MySQL without any issues, but I want to save the data from this package on postgres.
So here is what I have within the
application/config/database.php: